The present invention relates to a semiconductor testing apparatus for executing functional tests of a semiconductor device.
In case of executing functional tests of a semiconductor device, generally the semiconductor device is operated using the procedure of a testing program, thereby to determine whether it outputs an expected data or not. And from the result of the output, whether the semiconductor device is good or no good is judged. As a result of having a great variety of functions, however, in case of testing all functions of the semiconductor device, it is necessary to prepare a testing program for the respective functional test and to test all functions running these testing programs by turns. As a variety of functional tests of the semiconductor device, there are, for example, a test of read only memory(ROM), a test of random access memory(RAM), etc.
In the following, a conventional semiconductor testing apparatus 18 is elucidated in detail referring to FIG. 7. The conventional semiconductor testing apparatus 18 consists of a control unit 19 that is a central processing unit and so on, a memory 2 for storing a testing program 3 to execute each functional tests of a semiconductor device 8 and a hardware 6 for executing all functional tests of the semiconductor device 8. Usually as a testing program 3, plural programs (3a, 3b, - - - ) are prepared for the respective functional tests (T1, T2, - - - ) of the semiconductor device 8. The hardware 6 consists of plural units 6a, 6b, 6c, 6d, 6e, the respective units 6a, 6b, 6c, 6d, 6e taking shares of the respective functional tests (T1, T2, - - - ) of the semiconductor device 8.
The control unit 19 reads one of statements configured in the testing program 3 in the memory 2, decodes it and order the hardware 6 to execute the decoded statement. After the hardware 6 finish executing of the decoded statement, the control unit 19 reads the next statement configured in the testing program 3.
As statements configured in the testing program 3, there are, for example, a statement concerning the conditional setting for the hardware 6, a statement concerning the power-on for the hardware 6, a statement concerning the power-off for the hardware 6 and a statement concerning the execution of functional tests of the semiconductor device 8.
In case of this conventional example, for instance, after the hardware 6 finishes executing of the program 3a, the control unit 19 reads the next program 3b in the memory 2 and sets the condition of the respective units 6a, 6b, 6c, 6d, 6e of the hardware 6. In other words, in the case that it is not necessary to alter the conditional setting of the unit 6a, that is to say, even in the case that the conditional setting of the unit 6a in the next functional test may be the same as the previous conditional setting of the unit 6a, the condition of the unit 6a using the procedure of the program 3b is set again.
The statement concerning the power-off for the hardware 6 is configured at the end of the respective programs (3a, 3b, - - - ) for the purpose of protecting the semiconductor testing apparatus 18 and the semiconductor device 8. The statement concerning the power-off for the hardware 6 is executed by the control unit 19 and it turns off power to the hardware 6 by the control unit 19. And in the occasion that the next functional test is executed, the statement concerning the power-on for the hardware 6 is executed by the control unit 19. But in the case that the conditional setting of the hardware 6 in the next functional test is the same as the previous conditional setting of the hardware 6, or in the case that to alter the conditional setting of the hardware 6 under the power-on has no adversely influence upon the semiconductor device 8 and the semiconductor testing apparatus 18, it is not necessary to turn off power to the hardware 6.
In the above-mentioned two cases, unnecessary statement concerning the conditional setting for the hardware 6, unnecessary statement concerning the power-off for the hardware 6 and unnecessary statement concerning the power-on for the hardware 6 has been executed and it has wasted time. As a result, there was a defect that the conventional semiconductor testing apparatus 18 takes unnecessarily long time to test all functions of the semiconductor device 8.
Hitherto, as for the means to avoid taking this unnecessarily long time, the respective programs (3a, 3b, - - - ) are optimized so that a renewal testing program deleted all of unnecessary statements is drawn up. And an example of an optimization processing system is shown in FIG. 6. In the case shown in FIG. 6, a testing program 15 is optimized and a renewal testing program 17 is drawn up, wherein all of unnecessary statement is deleted by the optimization processing system 16.
In case of this example shown in FIG. 6, however, it is necessary to develop each system and each software to optimize each programs (15a, 15b, - - - ) to prepare for testing the respective functions of the semiconductor device. And as a result a huge cost and process are required.